Function patchCode

compile.go:1771–1847

}}}

(context *funcContext)

} // }}}

func patchCode(context *funcContext) { // {{{
	maxreg := 1
	if np := int(context.Proto.NumParameters); np > 1 {
		maxreg = np
	}
	moven := 0
	code := context.Code.List()
	for pc := 0; pc < len(code); pc++ {
		inst := code[pc]
		curop := opGetOpCode(inst)
		switch curop {
		case OP_CLOSURE:
			pc += int(context.Proto.FunctionPrototypes[opGetArgBx(inst)].NumUpvalues)
			moven = 0
			continue
		case OP_SETGLOBAL, OP_SETUPVAL, OP_EQ, OP_LT, OP_LE, OP_TEST,
			OP_TAILCALL, OP_RETURN, OP_FORPREP, OP_FORLOOP, OP_TFORLOOP,
			OP_SETLIST, OP_CLOSE:
			/* nothing to do */
		case OP_CALL:
			if reg := opGetArgA(inst) + opGetArgC(inst) - 2; reg > maxreg {
				maxreg = reg
			}
		case OP_VARARG:
			if reg := opGetArgA(inst) + opGetArgB(inst) - 1; reg > maxreg {
				maxreg = reg
			}
		case OP_SELF:
			if reg := opGetArgA(inst) + 1; reg > maxreg {
				maxreg = reg
			}
		case OP_LOADNIL:
			if reg := opGetArgB(inst); reg > maxreg {
				maxreg = reg
			}
		case OP_JMP: // jump to jump optimization
			distance := 0
			count := 0 // avoiding infinite loops
			for jmp := inst; opGetOpCode(jmp) == OP_JMP && count < 5; jmp = context.Code.At(pc + distance + 1) {
				d := context.GetLabelPc(opGetArgSbx(jmp)) - pc
				if d > opMaxArgSbx {
					if distance == 0 {
						raiseCompileError(context, context.Proto.LineDefined, "too long to jump.")
					}
					break
				}
				distance = d
				count++
			}
			if distance == 0 {
				context.Code.SetOpCode(pc, OP_NOP)
			} else {
				context.Code.SetSbx(pc, distance)
			}
		default:
			if reg := opGetArgA(inst); reg > maxreg {
				maxreg = reg
			}